Data storage systems are arrangements of hardware and software that include one or more storage processors coupled to arrays of non-volatile storage devices, such as magnetic disk drives, electronic flash drives, and/or optical drives, for example. The storage processors service storage requests, arriving from host machines (“hosts”), which specify files or other data elements to be written, read, created, or deleted, for example. Software running on the storage processors manages incoming storage requests and performs various data processing tasks to organize and secure the data elements stored on the non-volatile storage devices.
Data storage systems commonly store data objects, such as LUNs (Logical UNits), file systems, virtual machine disks, and/or other types of objects, which the data storage systems make accessible to hosts for reading and/or writing. Administrators may specify settings for data objects at their times of creation. Such settings may include, for example, whether a data object is thick or thin. As is known, a “thick” data object is one that has a maximum predetermined size that is fully space-guaranteed. For example, if an administrator creates a thick data object and specifies a 10 GB size, then a data storage system hosting that object reserves a full 10 GB of storage space, regardless of the amount of storage space that the object actually consumes. As is further known, a “thin” data object is one that is not fully space-guaranteed. Rather, reserved space for a thin data object grows in response to that object being written-to, e.g., on demand as additional storage space is needed.